Great Divide Brewing Company: 21st Anniversary

Official description from the brewery:
This American sour is a celebration of 21 years of brewing with Bold Character. This commemorative release opens up with bright, tart, kiwi and citrus notes before mellowing out with a hint of oak and subtle white wine-like character. Soured with lactobacillus and brettanomyces and aged for 9 months in wine barrels, 21st Anniversary is notably complex while retaining a delicate approachability.